The field of this invention is crossover tools frequently used in gravel packing operations and features of such tools post gravel packing, which allow chemical treating or packer inflation.
Crossover tools are frequently used in performing gravel-packing operations. They allow the gravel to pass through a packer and exit to an annular space outside one or more screens. The returns pass through the screen up a wash pipe and back through the crossover and out into the annulus above the packer for the trip to the surface. After deposition of the gravel, the crossover tool is picked up so that remaining gravel in the tubing can be reversed out with fluid pumped down the annulus above the packer.
Following gravel pack operation, the need may arise to acid treat the gravel pack area around the screens. In the past the gravel packing service tool assembly, including the crossover had to be pulled out and the treating string run in. The present invention presents a crossover tool with modifications to allow pumping down the string through the crossover tool, after the gravel packing operation is concluded so as to eliminate a trip out of the hole for acid treating. It also allows the excess chemical to be reversed out using a unique assembly that captures a plug that was used to shift a sleeve, on that sleeve during reverse flow.
In prior gravel packing techniques that used isolators in conjunction with the screens, it was also the practice to pull the gravel packing assembly, including the cross-over, and run in with another string to selectively inflate the external casing packers in the gravel pack zone. The present invention with the access provided through the crossover tool after the gravel packing allows such packers to be inflated in the same trip. This prior two-trip procedure is illustrated in U.S. Pat. No. 6,311,772. With the present invention the technique described in that patent can be streamlined.
Relevant patents that show gravel packing or sliding sleeve devices in downhole tools are U.S. Pat. Nos. 2,994,280; 4,424,864; 4,427,070; 4,520,870; 5,411,095; 5,597,040 and 5,823,254.
Those skilled in the art will be better able to appreciate the value of the invention from a description of the preferred embodiment and the claims below.
A crossover tool is disclosed that permits access through to the wash pipe below after the conclusion of a known gravel packing operation. A ball is trapped to a sleeve after shifting it so as to allow flow through the crossover for acid treatment in the screen area and a reversing out procedure to remove excess acid. Alternatively, pressure delivered through the wash pipe can operate packers, as part of a gravel packing procedure as outlined in two steps in U.S. Pat. No. 6,311,772 is a single trip. The acid treating or other downhole operation through the wash pipe can also be accomplished in a single trip with the gravel packing assembly.